There was a guy on CO4x4 that did it. However he had to modify the firewall, and he kept the entire jeep drive line (including the d30&35). However, 10mpg with a 4.0 is enough to make me love my POS 3.0
PZ
EDIT: just found it http://www.colorado4x4.org/vbb/showthread.php?t=47594
That's a very good friend of mine's rig. He used an 87 Toyota truck frame & cab. He had a clean XJ that he rolled on Fireman's Hill up on Lefthand. He proceed to put the 4 liter, front clip, XJ suspension, and axles on the Toyota. The front fenders were crazy custom. The rear half were Toyota & the front half were XJ. It looked like an MJ but with a full frame.
He quicked swapped the D30 & D35 out for a set of D44's from a Waggy. They now live under my brother in law's XJ. Terry ended up rolling the Xota on the way to Moab a couple of years ago and parted quite a bit of it out. He ended up just building an XJ to save the crazy custom fab work to make another Jeep-Yota.
I wheeled with Terry & his Xota all around Moab, BV Carnage, Blanca, Chinamans. It was one of the most capable rigs I've wheeled with. It climbed almost anything he tried.